(1/a^2- 1/b^2)因式分解得(1/a+1/b)(1/a-1/b)
所以结果是(1/a+1/b)/(1/a-1/b)
上下同乘以ab,化简得(b+a)/(b-a)
(1/a+1/b)²除以 (1/a²- 1/b²)
=(1/a+1/b)²÷(1/a+1/b)(1/a-1/b)
=(1/a+1/b)÷(1/a-1/b)
=(a+b)/ab÷[(b-a)/ab]
=(a+b/(b-a)
(1/a+1/b)²除以(1/a²-1/b²)
=(1/a+1/b)²除以【(1/a+1/b)(1/a-1/b)】
=(1/a+1/b)/(1/a-1/b)
=(b+a)/(b-a)
=(1/a+1/b)^2 /[(1/a- 1/b)(1/a+1/b)]
=(1/a+1/b)/ (1/a- 1/b)
=(a+b)/(b-a)
=(b+a)/(b-a)